Genetic Polymorphism and Association of KAP16.6 Gene with Pashmina Fiber Traits in Changthangi Goats

ABSTRACT

Pashmina is the fine undercoat of the Changthangi goats (Capra hircus) with Keratin-associated proteins (KAPs) as one of its main structural components. KAPs form a semi-rigid matrix in which the Keratin intermediate filaments (KIFs) are embedded. In the present study, an attempt was made to elucidate the polymorphism of KAP16.6 gene loci and its association with fiber yield and quality traits (fine yield, mean fiber diameter, mean fiber length, and guard hair percentage). A total of 103 animals of Changthangi goats were randomly selected and genomic DNA was isolated from blood samples. After amplification of the coding region of KAP16.6 (254 bp) gene, restriction digestion with HindIII enzyme (AAG/CTT) produced two polymorphic patterns in the Changthangi goats. The genotypic distribution of the designated genotypes A₁A₁ (0.0), A₂A₂ (0.379), and A₁A₂ (0.621) of KAP16.6 gene varied significantly (p < .01) from Hardy-Weinberg equilibrium. Missense mutation AGC (Serine) > AAC (Asparagine) was identified at KAP16.6 locus in Changthangi goats for the first time. The genetic variability parameters for the gene loci analyzed were: heterozygosity value 0.4283, PIC: 0.3366, effective allele no 1.7492 and Shannon index (I) of 0.6196. The estimated PIC value reflected median polymorphism exhibited by the Changthangi goat population under study for the selected gene. Statistical analysis further revealed a significant effect of KAP16.6 genotype on the fiber length (p < .05) whereas the effect was nonsignificant for other Pashmina production traits under study. The results from the present study have practical significance in the breeding plans for Changthangi goats in this region for improved production performance.

摘要

羊绒层是昌盛吉山羊（Capra hircus）精细的内毛，其主要结构成分之一是角蛋白相关蛋白（KAPs）. 角蛋白相关蛋白形成半刚性基质，其中角蛋白中间丝（KIF）嵌入其中. 本研究试图阐明角蛋白相关蛋白16.6基因座的多态性及其与纤维产量和品质性状（细度、平均纤维直径、平均纤维长度和护发率）的关系. 随机选择长滩吉山羊103只，从血样中分离基因组DNA。在扩增角蛋白相关蛋白16.6（254bp）基因编码区后，用HindIII酶（AAG/CTT）限制性酶切，在长滩吉山羊中产生两种多态性. KAP16.6基因A1A1（0.0）、A2A2（0.379）和A1A2（0.621）的基因型分布与Hardy-Weinberg平衡有显著差异（p<.01）. 首次在长滩山羊KAP16.6位点发现了AGC（丝氨酸）>AAC（天冬酰胺）的错义突变. 基因座的遗传变异参数为: 杂合度值-0.4283，PIC-0.3366，有效等位基因no.7492，Shannon指数（I）0.6196. 估计的PIC值反映了所选基因研究中的昌成吉山羊群体表现出的中位数多态性. 统计分析进一步显示角蛋白相关蛋白16.6基因型对纤维长度有显著影响（p<.05），而对其他羊驼生产性状的影响则不显著. 本研究结果对该地区长滩基山羊的育种计划，提高生产性能具有实际意义.

KEYWORDS:

• Characterization
• diversity
• Pashmina
• polymorphism
• sequence

关键词:

• 特征
• 多样性
• 帕什米纳
• 多态性
• 序列

Acknowledgments

The authors are highly thankful to ICAR-National Agricultural Science Fund (NASF) for financial assistance during this work (NASF/GTR-5006/2015-16). The authors want to pay sincere thanks to Dean, FVSc & AH, SKUAST-K for providing all possible assistance and appreciation for completing this study. The authors are highly grateful to Dr. Feroz Din Sheikh for his support in sample collection during this study. 

Disclosure statement

The authors declare no potential conflict of interest for the manuscript.

Supplementary material

Supplemental data for this article can be accessed on the publisher’s website.

Additional information

Funding

This work was supported by the ICAR-National Agricultural Science Fund (NASF)” with grant ID: ”NASF/GTR-5006/2015-16.